The "Model Path" if you will is as follows
3D Model in .STEP (such as from Solidworks or Autodesk) > Mesh in .stl (such as a thingiverse file) > Gcode in .gcode (from cura) >
Instructions to printer in .gcode (from matter controller or similar) > Movement of motors (controlled by firmware) > Printed Object
The program that sends instructions to the printer is typically referred to as the "Host Software" Examples include:
Mattercontrol
Craftware
Repitier
Octoprint
Slic3r?
and more.
I suggest that you see the wiki for further details and best of luck.